1. Field of the Invention
The present invention relates to a cloud computing system, a method for controlling the same.
2. Description of the Related Art
In recent years, a technology referred to as a “cloud computing system”, which is capable of employing various applications operated by a server on the Internet, has been proposed. In the cloud computing system, a cloud service vendor provides a virtual computer (Virtual Machine: VM) and storage on the Internet, and thus is capable of providing various services using these. An application developer pays a usage fee to the cloud service vendor and uses a service provided by the cloud computing system, which allows the application developer to develop a cloud application.
In the application employing the cloud computing system, the performance of the application can be improved by increasing the number of VMs to be used. However, in general, a fee for using a cloud service may be significantly different depending on the number of VMs. Thus, the number of VMs is dynamically increased or decreased depending on the load on an application and the amount of transactions, and a service is provided using the appropriate number of VMs, which is very important from the viewpoint of both performance and cost.
Japanese Patent Laid-Open No. 2008-234356 discloses a system for detecting a reversibly degeneracy-enabled server. While a plurality of servers performs processing in parallel manner, the system measures the processing load on the respective servers. When the processing load is low as a result of measurement, the system detects a server for which processing may be halted based on the dependency of processing performed by the respective servers, and halts processing when possible.